.TH std::iswdigit 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::iswdigit \- std::iswdigit

.SH Synopsis
   Defined in header <cwctype>
   int iswdigit( wint_t ch );

   Checks if the given wide character corresponds (if narrowed) to one of the ten
   decimal digit characters 0123456789.

   If the value of ch is neither representable as a wchar_t nor equal to the value of
   the macro WEOF, the behavior is undefined.

.SH Parameters

   ch - wide character

.SH Return value

   Non-zero value if the wide character is a numeric character, zero otherwise.

.SH Notes

   std::iswdigit and std::iswxdigit are the only standard wide character classification
   functions that are not affected by the currently installed C locale.

.SH Example

   Some locales offer additional character classes that detect non-ASCII digits


// Run this code

 #include <clocale>
 #include <cwctype>
 #include <iostream>

 void test(wchar_t a3, wchar_t u3, wchar_t j3)
 {
     std::wcout << std::boolalpha
                << "\\t   '" << a3 << "'   '" << u3 << "'  '" << j3  << "'\\n"
                << "iswdigit: "
                << (bool)std::iswdigit(a3) << "  "
                << (bool)std::iswdigit(u3) << " "
                << (bool)std::iswdigit(j3) << '\\n'
                << "jdigit:   "
                << (bool)std::iswctype(a3, std::wctype("jdigit")) << ' '
                << (bool)std::iswctype(u3, std::wctype("jdigit")) << ' '
                << (bool)std::iswctype(j3, std::wctype("jdigit")) << '\\n';
 }

 int main()
 {
     wchar_t a3 = L'3';  // the ASCII digit 3
     wchar_t u3 = L'三'; // the CJK numeral 3
     wchar_t j3 = L'３'; // the full-width digit 3

     std::setlocale(LC_ALL, "en_US.utf8");
     std::wcout << "In American locale:\\n";
     test(a3, u3, j3);

     std::wcout << "\\nIn Japanese locale:\\n";
     std::setlocale(LC_ALL, "ja_JP.utf8");
     test(a3, u3, j3);
 }

.SH Possible output:

 In American locale:
            '3'   '三'  '３'
 iswdigit: true  false false
 jdigit:   false false false

 In Japanese locale:
            '3'   '三'  '３'
 iswdigit: true  false false
 jdigit:   false false true

.SH See also

   isdigit(std::locale) checks if a character is classified as a digit by a locale
                        \fI(function template)\fP
   isdigit              checks if a character is a digit
                        \fI(function)\fP
   C documentation for
   iswdigit

        ASCII values            characters    iscntrl  isprint  isspace  isblank  isgraph  ispunct  isalnum  isalpha  isupper  islower  isdigit  isxdigit
decimal hexadecimal   octal                   iswcntrl iswprint iswspace iswblank iswgraph iswpunct iswalnum iswalpha iswupper iswlower iswdigit iswxdigit
0–8     \\x0–\\x8     \\0–\\10    control codes   ≠0       0        0        0        0        0        0        0        0        0        0        0
                              (NUL, etc.)
9       \\x9         \\11       tab (\\t)        ≠0       0        ≠0       ≠0       0        0        0        0        0        0        0        0
                              whitespaces
10–13   \\xA–\\xD     \\12–\\15   (\\n, \\v, \\f,    ≠0       0        ≠0       0        0        0        0        0        0        0        0        0
                              \\r)
14–31   \\xE–\\x1F    \\16–\\37   control codes   ≠0       0        0        0        0        0        0        0        0        0        0        0
32      \\x20        \\40       space           0        ≠0       ≠0       ≠0       0        0        0        0        0        0        0        0
33–47   \\x21–\\x2F   \\41–\\57   !"#$%&'()*+,-./ 0        ≠0       0        0        ≠0       ≠0       0        0        0        0        0        0
48–57   \\x30–\\x39   \\60–\\71   0123456789      0        ≠0       0        0        ≠0       0        ≠0       0        0        0        ≠0       ≠0
58–64   \\x3A–\\x40   \\72–\\100  :;<=>?@         0        ≠0       0        0        ≠0       ≠0       0        0        0        0        0        0
65–70   \\x41–\\x46   \\101–\\106 ABCDEF          0        ≠0       0        0        ≠0       0        ≠0       ≠0       ≠0       0        0        ≠0
71–90   \\x47–\\x5A   \\107–\\132 GHIJKLMNOP      0        ≠0       0        0        ≠0       0        ≠0       ≠0       ≠0       0        0        0
                              QRSTUVWXYZ
91–96   \\x5B–\\x60   \\133–\\140 [\\]^_`          0        ≠0       0        0        ≠0       ≠0       0        0        0        0        0        0
97–102  \\x61–\\x66   \\141–\\146 abcdef          0        ≠0       0        0        ≠0       0        ≠0       ≠0       0        ≠0       0        ≠0
103–122 \\x67–\\x7A   \\147–\\172 ghijklmnop      0        ≠0       0        0        ≠0       0        ≠0       ≠0       0        ≠0       0        0
                              qrstuvwxyz
123–126 \\x7B–\\x7E   \\172–\\176 {|}~            0        ≠0       0        0        ≠0       ≠0       0        0        0        0        0        0
127     \\x7F        \\177      backspace       ≠0       0        0        0        0        0        0        0        0        0        0        0
                              character (DEL)
